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Diffstat (limited to 'c/src/lib/libnetworking/netinet/tcp_usrreq.c')
-rw-r--r--c/src/lib/libnetworking/netinet/tcp_usrreq.c840
1 files changed, 840 insertions, 0 deletions
diff --git a/c/src/lib/libnetworking/netinet/tcp_usrreq.c b/c/src/lib/libnetworking/netinet/tcp_usrreq.c
new file mode 100644
index 0000000000..ecd9d95636
--- /dev/null
+++ b/c/src/lib/libnetworking/netinet/tcp_usrreq.c
@@ -0,0 +1,840 @@
+/*
+ * Copyright (c) 1982, 1986, 1988, 1993
+ * The Regents of the University of California. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ * must display the following acknowledgement:
+ * This product includes software developed by the University of
+ * California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * From: @(#)tcp_usrreq.c 8.2 (Berkeley) 1/3/94
+ * $Id$
+ */
+
+#include "opt_tcpdebug.h"
+
+#include <sys/param.h>
+#include <sys/queue.h>
+#include <sys/systm.h>
+#include <sys/kernel.h>
+#include <sys/sysctl.h>
+#include <sys/malloc.h>
+#include <sys/mbuf.h>
+#include <sys/socket.h>
+#include <sys/socketvar.h>
+#include <sys/protosw.h>
+#include <sys/errno.h>
+#include <sys/stat.h>
+
+#include <net/if.h>
+#include <net/route.h>
+
+#include <netinet/in.h>
+#include <netinet/in_systm.h>
+#include <netinet/ip.h>
+#include <netinet/in_pcb.h>
+#include <netinet/in_var.h>
+#include <netinet/ip_var.h>
+#include <netinet/tcp.h>
+#include <netinet/tcp_fsm.h>
+#include <netinet/tcp_seq.h>
+#include <netinet/tcp_timer.h>
+#include <netinet/tcp_var.h>
+#include <netinet/tcpip.h>
+#ifdef TCPDEBUG
+#include <netinet/tcp_debug.h>
+#endif
+
+/*
+ * TCP protocol interface to socket abstraction.
+ */
+extern char *tcpstates[];
+
+static int tcp_attach __P((struct socket *));
+static int tcp_connect __P((struct tcpcb *, struct mbuf *));
+static struct tcpcb *
+ tcp_disconnect __P((struct tcpcb *));
+static struct tcpcb *
+ tcp_usrclosed __P((struct tcpcb *));
+
+#ifdef TCPDEBUG
+#define TCPDEBUG0 int ostate
+#define TCPDEBUG1() ostate = tp ? tp->t_state : 0
+#define TCPDEBUG2(req) if (tp && (so->so_options & SO_DEBUG)) \
+ tcp_trace(TA_USER, ostate, tp, 0, req)
+#else
+#define TCPDEBUG0
+#define TCPDEBUG1()
+#define TCPDEBUG2(req)
+#endif
+
+/*
+ * TCP attaches to socket via pru_attach(), reserving space,
+ * and an internet control block.
+ */
+static int
+tcp_usr_attach(struct socket *so, int proto)
+{
+ int s = splnet();
+ int error;
+ struct inpcb *inp = sotoinpcb(so);
+ struct tcpcb *tp = 0;
+ TCPDEBUG0;
+
+ TCPDEBUG1();
+ if (inp) {
+ error = EISCONN;
+ goto out;
+ }
+
+ error = tcp_attach(so);
+ if (error)
+ goto out;
+
+ if ((so->so_options & SO_LINGER) && so->so_linger == 0)
+ so->so_linger = TCP_LINGERTIME * hz;
+ tp = sototcpcb(so);
+out:
+ TCPDEBUG2(PRU_ATTACH);
+ splx(s);
+ return error;
+}
+
+/*
+ * pru_detach() detaches the TCP protocol from the socket.
+ * If the protocol state is non-embryonic, then can't
+ * do this directly: have to initiate a pru_disconnect(),
+ * which may finish later; embryonic TCB's can just
+ * be discarded here.
+ */
+static int
+tcp_usr_detach(struct socket *so)
+{
+ int s = splnet();
+ int error = 0;
+ struct inpcb *inp = sotoinpcb(so);
+ struct tcpcb *tp;
+ TCPDEBUG0;
+
+ if (inp == 0) {
+ splx(s);
+ return EINVAL; /* XXX */
+ }
+ tp = intotcpcb(inp);
+ TCPDEBUG1();
+ if (tp->t_state > TCPS_LISTEN)
+ tp = tcp_disconnect(tp);
+ else
+ tp = tcp_close(tp);
+
+ TCPDEBUG2(PRU_DETACH);
+ splx(s);
+ return error;
+}
+
+#define COMMON_START() TCPDEBUG0; \
+ do { \
+ if (inp == 0) { \
+ splx(s); \
+ return EINVAL; \
+ } \
+ tp = intotcpcb(inp); \
+ TCPDEBUG1(); \
+ } while(0)
+
+#define COMMON_END(req) out: TCPDEBUG2(req); splx(s); return error; goto out
+
+
+/*
+ * Give the socket an address.
+ */
+static int
+tcp_usr_bind(struct socket *so, struct mbuf *nam)
+{
+ int s = splnet();
+ int error = 0;
+ struct inpcb *inp = sotoinpcb(so);
+ struct tcpcb *tp;
+ struct sockaddr_in *sinp;
+
+ COMMON_START();
+
+ /*
+ * Must check for multicast addresses and disallow binding
+ * to them.
+ */
+ sinp = mtod(nam, struct sockaddr_in *);
+ if (sinp->sin_family == AF_INET &&
+ IN_MULTICAST(ntohl(sinp->sin_addr.s_addr))) {
+ error = EAFNOSUPPORT;
+ goto out;
+ }
+ error = in_pcbbind(inp, nam);
+ if (error)
+ goto out;
+ COMMON_END(PRU_BIND);
+
+}
+
+/*
+ * Prepare to accept connections.
+ */
+static int
+tcp_usr_listen(struct socket *so)
+{
+ int s = splnet();
+ int error = 0;
+ struct inpcb *inp = sotoinpcb(so);
+ struct tcpcb *tp;
+
+ COMMON_START();
+ if (inp->inp_lport == 0)
+ error = in_pcbbind(inp, NULL);
+ if (error == 0)
+ tp->t_state = TCPS_LISTEN;
+ COMMON_END(PRU_LISTEN);
+}
+
+/*
+ * Initiate connection to peer.
+ * Create a template for use in transmissions on this connection.
+ * Enter SYN_SENT state, and mark socket as connecting.
+ * Start keep-alive timer, and seed output sequence space.
+ * Send initial segment on connection.
+ */
+static int
+tcp_usr_connect(struct socket *so, struct mbuf *nam)
+{
+ int s = splnet();
+ int error = 0;
+ struct inpcb *inp = sotoinpcb(so);
+ struct tcpcb *tp;
+ struct sockaddr_in *sinp;
+
+ COMMON_START();
+
+ /*
+ * Must disallow TCP ``connections'' to multicast addresses.
+ */
+ sinp = mtod(nam, struct sockaddr_in *);
+ if (sinp->sin_family == AF_INET
+ && IN_MULTICAST(ntohl(sinp->sin_addr.s_addr))) {
+ error = EAFNOSUPPORT;
+ goto out;
+ }
+
+ if ((error = tcp_connect(tp, nam)) != 0)
+ goto out;
+ error = tcp_output(tp);
+ COMMON_END(PRU_CONNECT);
+}
+
+/*
+ * Initiate disconnect from peer.
+ * If connection never passed embryonic stage, just drop;
+ * else if don't need to let data drain, then can just drop anyways,
+ * else have to begin TCP shutdown process: mark socket disconnecting,
+ * drain unread data, state switch to reflect user close, and
+ * send segment (e.g. FIN) to peer. Socket will be really disconnected
+ * when peer sends FIN and acks ours.
+ *
+ * SHOULD IMPLEMENT LATER PRU_CONNECT VIA REALLOC TCPCB.
+ */
+static int
+tcp_usr_disconnect(struct socket *so)
+{
+ int s = splnet();
+ int error = 0;
+ struct inpcb *inp = sotoinpcb(so);
+ struct tcpcb *tp;
+
+ COMMON_START();
+ tp = tcp_disconnect(tp);
+ COMMON_END(PRU_DISCONNECT);
+}
+
+/*
+ * Accept a connection. Essentially all the work is
+ * done at higher levels; just return the address
+ * of the peer, storing through addr.
+ */
+static int
+tcp_usr_accept(struct socket *so, struct mbuf *nam)
+{
+ int s = splnet();
+ int error = 0;
+ struct inpcb *inp = sotoinpcb(so);
+ struct tcpcb *tp;
+
+ COMMON_START();
+ in_setpeeraddr(inp, nam);
+ COMMON_END(PRU_ACCEPT);
+}
+
+/*
+ * Mark the connection as being incapable of further output.
+ */
+static int
+tcp_usr_shutdown(struct socket *so)
+{
+ int s = splnet();
+ int error = 0;
+ struct inpcb *inp = sotoinpcb(so);
+ struct tcpcb *tp;
+
+ COMMON_START();
+ socantsendmore(so);
+ tp = tcp_usrclosed(tp);
+ if (tp)
+ error = tcp_output(tp);
+ COMMON_END(PRU_SHUTDOWN);
+}
+
+/*
+ * After a receive, possibly send window update to peer.
+ */
+static int
+tcp_usr_rcvd(struct socket *so, int flags)
+{
+ int s = splnet();
+ int error = 0;
+ struct inpcb *inp = sotoinpcb(so);
+ struct tcpcb *tp;
+
+ COMMON_START();
+ tcp_output(tp);
+ COMMON_END(PRU_RCVD);
+}
+
+/*
+ * Do a send by putting data in output queue and updating urgent
+ * marker if URG set. Possibly send more data.
+ */
+static int
+tcp_usr_send(struct socket *so, int flags, struct mbuf *m, struct mbuf *nam,
+ struct mbuf *control)
+{
+ int s = splnet();
+ int error = 0;
+ struct inpcb *inp = sotoinpcb(so);
+ struct tcpcb *tp;
+
+ COMMON_START();
+ if (control && control->m_len) {
+ m_freem(control); /* XXX shouldn't caller do this??? */
+ if (m)
+ m_freem(m);
+ error = EINVAL;
+ goto out;
+ }
+
+ if(!(flags & PRUS_OOB)) {
+ sbappend(&so->so_snd, m);
+ if (nam && tp->t_state < TCPS_SYN_SENT) {
+ /*
+ * Do implied connect if not yet connected,
+ * initialize window to default value, and
+ * initialize maxseg/maxopd using peer's cached
+ * MSS.
+ */
+ error = tcp_connect(tp, nam);
+ if (error)
+ goto out;
+ tp->snd_wnd = TTCP_CLIENT_SND_WND;
+ tcp_mss(tp, -1);
+ }
+
+ if (flags & PRUS_EOF) {
+ /*
+ * Close the send side of the connection after
+ * the data is sent.
+ */
+ socantsendmore(so);
+ tp = tcp_usrclosed(tp);
+ }
+ if (tp != NULL)
+ error = tcp_output(tp);
+ } else {
+ if (sbspace(&so->so_snd) < -512) {
+ m_freem(m);
+ error = ENOBUFS;
+ goto out;
+ }
+ /*
+ * According to RFC961 (Assigned Protocols),
+ * the urgent pointer points to the last octet
+ * of urgent data. We continue, however,
+ * to consider it to indicate the first octet
+ * of data past the urgent section.
+ * Otherwise, snd_up should be one lower.
+ */
+ sbappend(&so->so_snd, m);
+ if (nam && tp->t_state < TCPS_SYN_SENT) {
+ /*
+ * Do implied connect if not yet connected,
+ * initialize window to default value, and
+ * initialize maxseg/maxopd using peer's cached
+ * MSS.
+ */
+ error = tcp_connect(tp, nam);
+ if (error)
+ goto out;
+ tp->snd_wnd = TTCP_CLIENT_SND_WND;
+ tcp_mss(tp, -1);
+ }
+ tp->snd_up = tp->snd_una + so->so_snd.sb_cc;
+ tp->t_force = 1;
+ error = tcp_output(tp);
+ tp->t_force = 0;
+ }
+ COMMON_END((flags & PRUS_OOB) ? PRU_SENDOOB :
+ ((flags & PRUS_EOF) ? PRU_SEND_EOF : PRU_SEND));
+}
+
+/*
+ * Abort the TCP.
+ */
+static int
+tcp_usr_abort(struct socket *so)
+{
+ int s = splnet();
+ int error = 0;
+ struct inpcb *inp = sotoinpcb(so);
+ struct tcpcb *tp;
+
+ COMMON_START();
+ tp = tcp_drop(tp, ECONNABORTED);
+ COMMON_END(PRU_ABORT);
+}
+
+/*
+ * Fill in st_bklsize for fstat() operations on a socket.
+ */
+static int
+tcp_usr_sense(struct socket *so, struct stat *sb)
+{
+ int s = splnet();
+
+ sb->st_blksize = so->so_snd.sb_hiwat;
+ splx(s);
+ return 0;
+}
+
+/*
+ * Receive out-of-band data.
+ */
+static int
+tcp_usr_rcvoob(struct socket *so, struct mbuf *m, int flags)
+{
+ int s = splnet();
+ int error = 0;
+ struct inpcb *inp = sotoinpcb(so);
+ struct tcpcb *tp;
+
+ COMMON_START();
+ if ((so->so_oobmark == 0 &&
+ (so->so_state & SS_RCVATMARK) == 0) ||
+ so->so_options & SO_OOBINLINE ||
+ tp->t_oobflags & TCPOOB_HADDATA) {
+ error = EINVAL;
+ goto out;
+ }
+ if ((tp->t_oobflags & TCPOOB_HAVEDATA) == 0) {
+ error = EWOULDBLOCK;
+ goto out;
+ }
+ m->m_len = 1;
+ *mtod(m, caddr_t) = tp->t_iobc;
+ if ((flags & MSG_PEEK) == 0)
+ tp->t_oobflags ^= (TCPOOB_HAVEDATA | TCPOOB_HADDATA);
+ COMMON_END(PRU_RCVOOB);
+}
+
+static int
+tcp_usr_sockaddr(struct socket *so, struct mbuf *nam)
+{
+ int s = splnet();
+ int error = 0;
+ struct inpcb *inp = sotoinpcb(so);
+ struct tcpcb *tp;
+
+ COMMON_START();
+ in_setsockaddr(inp, nam);
+ COMMON_END(PRU_SOCKADDR);
+}
+
+static int
+tcp_usr_peeraddr(struct socket *so, struct mbuf *nam)
+{
+ int s = splnet();
+ int error = 0;
+ struct inpcb *inp = sotoinpcb(so);
+ struct tcpcb *tp;
+
+ COMMON_START();
+ in_setpeeraddr(inp, nam);
+ COMMON_END(PRU_PEERADDR);
+}
+
+/*
+ * XXX - this should just be a call to in_control, but we need to get
+ * the types worked out.
+ */
+static int
+tcp_usr_control(struct socket *so, int cmd, caddr_t arg, struct ifnet *ifp)
+{
+ return in_control(so, cmd, arg, ifp);
+}
+
+/* xxx - should be const */
+struct pr_usrreqs tcp_usrreqs = {
+ tcp_usr_abort, tcp_usr_accept, tcp_usr_attach, tcp_usr_bind,
+ tcp_usr_connect, pru_connect2_notsupp, tcp_usr_control, tcp_usr_detach,
+ tcp_usr_disconnect, tcp_usr_listen, tcp_usr_peeraddr, tcp_usr_rcvd,
+ tcp_usr_rcvoob, tcp_usr_send, tcp_usr_sense, tcp_usr_shutdown,
+ tcp_usr_sockaddr
+};
+
+/*
+ * Common subroutine to open a TCP connection to remote host specified
+ * by struct sockaddr_in in mbuf *nam. Call in_pcbbind to assign a local
+ * port number if needed. Call in_pcbladdr to do the routing and to choose
+ * a local host address (interface). If there is an existing incarnation
+ * of the same connection in TIME-WAIT state and if the remote host was
+ * sending CC options and if the connection duration was < MSL, then
+ * truncate the previous TIME-WAIT state and proceed.
+ * Initialize connection parameters and enter SYN-SENT state.
+ */
+static int
+tcp_connect(tp, nam)
+ register struct tcpcb *tp;
+ struct mbuf *nam;
+{
+ struct inpcb *inp = tp->t_inpcb, *oinp;
+ struct socket *so = inp->inp_socket;
+ struct tcpcb *otp;
+ struct sockaddr_in *sin = mtod(nam, struct sockaddr_in *);
+ struct sockaddr_in *ifaddr;
+ int error;
+ struct rmxp_tao *taop;
+ struct rmxp_tao tao_noncached;
+
+ if (inp->inp_lport == 0) {
+ error = in_pcbbind(inp, NULL);
+ if (error)
+ return error;
+ }
+
+ /*
+ * Cannot simply call in_pcbconnect, because there might be an
+ * earlier incarnation of this same connection still in
+ * TIME_WAIT state, creating an ADDRINUSE error.
+ */
+ error = in_pcbladdr(inp, nam, &ifaddr);
+ if (error)
+ return error;
+ oinp = in_pcblookuphash(inp->inp_pcbinfo,
+ sin->sin_addr, sin->sin_port,
+ inp->inp_laddr.s_addr != INADDR_ANY ? inp->inp_laddr
+ : ifaddr->sin_addr,
+ inp->inp_lport, 0);
+ if (oinp) {
+ if (oinp != inp && (otp = intotcpcb(oinp)) != NULL &&
+ otp->t_state == TCPS_TIME_WAIT &&
+ otp->t_duration < TCPTV_MSL &&
+ (otp->t_flags & TF_RCVD_CC))
+ otp = tcp_close(otp);
+ else
+ return EADDRINUSE;
+ }
+ if (inp->inp_laddr.s_addr == INADDR_ANY)
+ inp->inp_laddr = ifaddr->sin_addr;
+ inp->inp_faddr = sin->sin_addr;
+ inp->inp_fport = sin->sin_port;
+ in_pcbrehash(inp);
+
+ tp->t_template = tcp_template(tp);
+ if (tp->t_template == 0) {
+ in_pcbdisconnect(inp);
+ return ENOBUFS;
+ }
+
+ /* Compute window scaling to request. */
+ while (tp->request_r_scale < TCP_MAX_WINSHIFT &&
+ (TCP_MAXWIN << tp->request_r_scale) < so->so_rcv.sb_hiwat)
+ tp->request_r_scale++;
+
+ soisconnecting(so);
+ tcpstat.tcps_connattempt++;
+ tp->t_state = TCPS_SYN_SENT;
+ tp->t_timer[TCPT_KEEP] = tcp_keepinit;
+ tp->iss = tcp_iss; tcp_iss += TCP_ISSINCR/2;
+ tcp_sendseqinit(tp);
+
+ /*
+ * Generate a CC value for this connection and
+ * check whether CC or CCnew should be used.
+ */
+ if ((taop = tcp_gettaocache(tp->t_inpcb)) == NULL) {
+ taop = &tao_noncached;
+ bzero(taop, sizeof(*taop));
+ }
+
+ tp->cc_send = CC_INC(tcp_ccgen);
+ if (taop->tao_ccsent != 0 &&
+ CC_GEQ(tp->cc_send, taop->tao_ccsent)) {
+ taop->tao_ccsent = tp->cc_send;
+ } else {
+ taop->tao_ccsent = 0;
+ tp->t_flags |= TF_SENDCCNEW;
+ }
+
+ return 0;
+}
+
+int
+tcp_ctloutput(op, so, level, optname, mp)
+ int op;
+ struct socket *so;
+ int level, optname;
+ struct mbuf **mp;
+{
+ int error = 0, s;
+ struct inpcb *inp;
+ register struct tcpcb *tp;
+ register struct mbuf *m;
+ register int i;
+
+ s = splnet();
+ inp = sotoinpcb(so);
+ if (inp == NULL) {
+ splx(s);
+ if (op == PRCO_SETOPT && *mp)
+ (void) m_free(*mp);
+ return (ECONNRESET);
+ }
+ if (level != IPPROTO_TCP) {
+ error = ip_ctloutput(op, so, level, optname, mp);
+ splx(s);
+ return (error);
+ }
+ tp = intotcpcb(inp);
+
+ switch (op) {
+
+ case PRCO_SETOPT:
+ m = *mp;
+ switch (optname) {
+
+ case TCP_NODELAY:
+ if (m == NULL || m->m_len < sizeof (int))
+ error = EINVAL;
+ else if (*mtod(m, int *))
+ tp->t_flags |= TF_NODELAY;
+ else
+ tp->t_flags &= ~TF_NODELAY;
+ break;
+
+ case TCP_MAXSEG:
+ if (m && (i = *mtod(m, int *)) > 0 && i <= tp->t_maxseg)
+ tp->t_maxseg = i;
+ else
+ error = EINVAL;
+ break;
+
+ case TCP_NOOPT:
+ if (m == NULL || m->m_len < sizeof (int))
+ error = EINVAL;
+ else if (*mtod(m, int *))
+ tp->t_flags |= TF_NOOPT;
+ else
+ tp->t_flags &= ~TF_NOOPT;
+ break;
+
+ case TCP_NOPUSH:
+ if (m == NULL || m->m_len < sizeof (int))
+ error = EINVAL;
+ else if (*mtod(m, int *))
+ tp->t_flags |= TF_NOPUSH;
+ else
+ tp->t_flags &= ~TF_NOPUSH;
+ break;
+
+ default:
+ error = ENOPROTOOPT;
+ break;
+ }
+ if (m)
+ (void) m_free(m);
+ break;
+
+ case PRCO_GETOPT:
+ *mp = m = m_get(M_WAIT, MT_SOOPTS);
+ m->m_len = sizeof(int);
+
+ switch (optname) {
+ case TCP_NODELAY:
+ *mtod(m, int *) = tp->t_flags & TF_NODELAY;
+ break;
+ case TCP_MAXSEG:
+ *mtod(m, int *) = tp->t_maxseg;
+ break;
+ case TCP_NOOPT:
+ *mtod(m, int *) = tp->t_flags & TF_NOOPT;
+ break;
+ case TCP_NOPUSH:
+ *mtod(m, int *) = tp->t_flags & TF_NOPUSH;
+ break;
+ default:
+ error = ENOPROTOOPT;
+ break;
+ }
+ break;
+ }
+ splx(s);
+ return (error);
+}
+
+/*
+ * tcp_sendspace and tcp_recvspace are the default send and receive window
+ * sizes, respectively. These are obsolescent (this information should
+ * be set by the route).
+ */
+u_long tcp_sendspace = 1024*16;
+SYSCTL_INT(_net_inet_tcp, TCPCTL_SENDSPACE, sendspace,
+ CTLFLAG_RW, &tcp_sendspace , 0, "");
+u_long tcp_recvspace = 1024*16;
+SYSCTL_INT(_net_inet_tcp, TCPCTL_RECVSPACE, recvspace,
+ CTLFLAG_RW, &tcp_recvspace , 0, "");
+
+/*
+ * Attach TCP protocol to socket, allocating
+ * internet protocol control block, tcp control block,
+ * bufer space, and entering LISTEN state if to accept connections.
+ */
+static int
+tcp_attach(so)
+ struct socket *so;
+{
+ register struct tcpcb *tp;
+ struct inpcb *inp;
+ int error;
+
+ if (so->so_snd.sb_hiwat == 0 || so->so_rcv.sb_hiwat == 0) {
+ error = soreserve(so, tcp_sendspace, tcp_recvspace);
+ if (error)
+ return (error);
+ }
+ error = in_pcballoc(so, &tcbinfo);
+ if (error)
+ return (error);
+ inp = sotoinpcb(so);
+ tp = tcp_newtcpcb(inp);
+ if (tp == 0) {
+ int nofd = so->so_state & SS_NOFDREF; /* XXX */
+
+ so->so_state &= ~SS_NOFDREF; /* don't free the socket yet */
+ in_pcbdetach(inp);
+ so->so_state |= nofd;
+ return (ENOBUFS);
+ }
+ tp->t_state = TCPS_CLOSED;
+ return (0);
+}
+
+/*
+ * Initiate (or continue) disconnect.
+ * If embryonic state, just send reset (once).
+ * If in ``let data drain'' option and linger null, just drop.
+ * Otherwise (hard), mark socket disconnecting and drop
+ * current input data; switch states based on user close, and
+ * send segment to peer (with FIN).
+ */
+static struct tcpcb *
+tcp_disconnect(tp)
+ register struct tcpcb *tp;
+{
+ struct socket *so = tp->t_inpcb->inp_socket;
+
+ if (tp->t_state < TCPS_ESTABLISHED)
+ tp = tcp_close(tp);
+ else if ((so->so_options & SO_LINGER) && so->so_linger == 0)
+ tp = tcp_drop(tp, 0);
+ else {
+ soisdisconnecting(so);
+ sbflush(&so->so_rcv);
+ tp = tcp_usrclosed(tp);
+ if (tp)
+ (void) tcp_output(tp);
+ }
+ return (tp);
+}
+
+/*
+ * User issued close, and wish to trail through shutdown states:
+ * if never received SYN, just forget it. If got a SYN from peer,
+ * but haven't sent FIN, then go to FIN_WAIT_1 state to send peer a FIN.
+ * If already got a FIN from peer, then almost done; go to LAST_ACK
+ * state. In all other cases, have already sent FIN to peer (e.g.
+ * after PRU_SHUTDOWN), and just have to play tedious game waiting
+ * for peer to send FIN or not respond to keep-alives, etc.
+ * We can let the user exit from the close as soon as the FIN is acked.
+ */
+static struct tcpcb *
+tcp_usrclosed(tp)
+ register struct tcpcb *tp;
+{
+
+ switch (tp->t_state) {
+
+ case TCPS_CLOSED:
+ case TCPS_LISTEN:
+ tp->t_state = TCPS_CLOSED;
+ tp = tcp_close(tp);
+ break;
+
+ case TCPS_SYN_SENT:
+ case TCPS_SYN_RECEIVED:
+ tp->t_flags |= TF_NEEDFIN;
+ break;
+
+ case TCPS_ESTABLISHED:
+ tp->t_state = TCPS_FIN_WAIT_1;
+ break;
+
+ case TCPS_CLOSE_WAIT:
+ tp->t_state = TCPS_LAST_ACK;
+ break;
+ }
+ if (tp && tp->t_state >= TCPS_FIN_WAIT_2) {
+ soisdisconnected(tp->t_inpcb->inp_socket);
+ /* To prevent the connection hanging in FIN_WAIT_2 forever. */
+ if (tp->t_state == TCPS_FIN_WAIT_2)
+ tp->t_timer[TCPT_2MSL] = tcp_maxidle;
+ }
+ return (tp);
+}
+